I was loaned my friend’s pair of Bose QC 25s for a few days. Below are my impressions of them; I only got a little less than a week with them, so my opinion is not as refined as I’d like it to be, but I think is substantive enough to warrant a review.

Fit and Form

The headphones come with a very attractive faux leather hard case. It is much more compact and space-efficient than the case for the QC 15s, and has a little holster for the included airplane adapter and what looks like a missing 1/4” adapter. The case is lined with blue suede and has an embossed image of the headphones in the proper folded position to store them.

The headphones themselves are very well made. The design is subtle and attractive and they are as small as I reasonably think true over-ears could be. The cups have a wide range of motion and can adapt to pretty much every head (I’d imagine, I don’t have that many heads). There is a two-position switch on the right cup that turns on and off the active noise cancelling. Different from the QC 15s, these can function without the ANC on, although that comes with some unpleasant changes to the sound signature. More on that later.

The headphones headband is fabric and the pads on the ear-cups are very soft and pleasant. I found that they were a little bit small for my ears, with the back edges sometimes resting against the helix of my ear. However, the drivers are angled such that there is more room for your pinna in such a compact form factor, which was appreciable. Overall, aside from the little bit of ear contact, they are very comfortable and I had no issue wearing them for extended periods of time.

The cable inserts into the left ear-cup with a 2.5mm TRS connector and has no locking mechanism, again unlike the QC 15s. I prefer this as I’ve never had an issue with the cable pulling out, and given that something grabs onto the cable in motion, I’d prefer it get pulled out as opposed to having the headphones come crashing down off my head.

They take a single AAA battery for their ANC. The cable features a three-button microphone that worked with Android and had good tactile identification of the point of actuation.

The cable terminates to an inflexible right angle 1/8” TRS connector, and I had no issue using it portably or at home.

Sound

I love the sound signature of these headphones when the ANC is on. The bass is full and deep, with good extension; the mids are rich and vocals present with good clarity and centering; the treble is bright and sparkly without being sibilant or painful. Overall, it’s very musical. However, when the ANC is turned off, it’s almost as if a veil has been dropped over the headphone. The bass drops out considerably, the mids become distant and a little bit grainy, and the treble loses its presence and recedes, heavily.

I had a major issue with these in terms of portability: for closed, mobile over-ears, these leak a ton. A friend next to me told me that he could easily distinguish lyrics in a song I was listening to, and I was only around comfortable listening volume, nothing obscenely loud inside the cans.

The soundstage on these is reasonably small, as they are closed. In binaural recordings, space is still very distinguished, but was slightly claustrophobic. These headphones don’t image or separate too well, so there was a little muddying of space when listening specifically for it.

The below commentary on sound signature is with the ANC on.

Bass

Songs used: Three Ralphs by DJ Shadow, The Entangled by Noisia, and Side B (Dope Song) by Danny Brown

The bass in these is full and satisfying. It extends well in the sub-bass range, although the mid-bass is noticeably more present than the sub-. Their bass didn’t overpower or reach into any other ranges, and was reasonably un-bloated. It’s not the fastest, but only got muddy and sloppy in the fastest-paced (bass-wise) songs that I could find (particularly in “I Never Woke Up in Handcuffs Before”, but only in that the bass basically formed a pretty solid floor, where I’ve found that headphones with extremely fast bass can distinguish more rhythm and dynamics in that regard).

Key descriptors: full, engaging, and grippy

Mids

Songs used: Ugly Cherries by PWR BTTM (live), Did We Live Too Fast by Got a Girl, and Gay Bar by Electric Six

The mids are a highlight for me. They are forward and detailed, lush and well-rounded. Male and female vocals both come through the mix very well and with good distinction. These made it very easy for me to focus on the vocals of any genre. I found that while it certainly is tolerable, separation and imaging could be better, as instruments tend to blend into each other a little bit. Not to the point that a track sounds mono-mastered from one location, but enough that it felt more like regions of an instrument than distinct placements.

Key descriptors: lush, detailed, and musical

Treble

Songs used: Time by Pink Floyd, Ageispolis by Aphex Twin, and From Kinshasa to the Moon by Mbongwana Star

Treble is very detailed ans bright without being particularly sibilant. I had no comfort issues in terms of listening to any songs with considerable treble emphasis. The detail was much appreciated and very noticeable. I also feel the necessity to point out that once there is an incredibly noticeable pull-back of the treble that is extremely dissatisfying. But again, I never listened to these for more than an hour without ANC on, and with it on, they were very enjoyable.

Key descriptors: bright, sparkly, and airy

Minutia and Miscellaneous

The noise cancelling on these i very good. They take a plane environment and turn it basically dead silent. You'll still hear if someone calls out your name, and the isolation, aside from of ambient noise, isn't particularly notable, but they do do active noise cancelling extremely well.

I really can’t overstate how weird the leakage was to me. For fully closed, (what looks to me to be) unported headphones, they leak a whole bunch. If you’re in a reasonably noisy environment or have a considerable distance from others in a quiet environment, it shouldn’t be an issue, but if you’re in close proximity to other people in a reasonably quiet environment, you’ll probably annoy them a little bit.

Wrap-Up

I enjoyed these headphones a lot. They were very musical, and great for casual listening. Upon analysis, they miss a few points, but hit on many more, thankfully.

I can’t comment as to whether or not these are worth their current $300, but that’s up to you.

Disclaimers

These headphones were not provided to me by Bose, they were loaned to me by a friend who has no association, professional or otherwise, with Bose. I am not being paid by anyone to write this review, to endorse the product reviewed, or for the content that I put in the review.

These headphones were powered by an Astell&Kern AK Junior, a Google Pixel, and by whatever soundcard is in the motherboard of my computer.

I have had these headphones for five days, and have spent a total of twenty hours listening to them. Although this is a short review period, I feel that the above commentary is reflective of my experience and accurate to it.

Update (3/12/17 9:00 PM EST): I added a section on the active noise cancelling under "Minutia and Miscellaneous", as it was pointed out to me that I had omitted a major mention of it, and it is one of the selling points of these headphones.